That Carcinogen Erin Brockovich Was So Worried About is in Miami's Tap Water

​A new study by the Environmental Working Group found that high levels of hexavalent chromium, a probably carcinogen also known as chromium-6, were found in the tap water of Miami, and many other American cities. Thirty-one of the 35 cities in the study were found to have some levels of the substance. Though it was detected in local tap water, Miami was one of the few cities were chromium-6 was found below the recommended safe levels. Chromium-6 has long been recognized as a carcinogen when inhaled, though there is debate over whether it may lead to cancer when ingested orally. Environmental activist Erin Brockovich, later played in a movie by Julia Roberts, brought the dangers of chromium-6 to national attention when she successfully helped win a multi-million dollar settlement for the citizens of Hinkley, California, after high levels of the substance were found in their tap water.

California has since adopted a suggested standard of having less than 0.06 parts per billion (ppb) of chromium-6 in public tap water. Though, most public water is only tested for total levels of chromium, and not for individual types of chromium.

The EWG study found that Miami's tap water only had 0.04 ppb of chromium-6. Most other cities had much higher levels of the pollutant.

So there's probably little to be worried about locally. However, experts advice that the best way to avoid chromium-6 and other impurities in tap water is to filter it before use.